On Tue, May 19, 2020 at 8:25 PM Marco Elver <elver@xxxxxxxxxx> wrote: > > During early boot, while KASAN is not yet initialized, it is possible to > enter reporting code-path and end up in kasan_report(). While > uninitialized, the branch there prevents generating any reports, > however, under certain circumstances when branches are being traced > (TRACE_BRANCH_PROFILING), we may recurse deep enough to cause kernel > reboots without warning. > > To prevent similar issues in future, we should disable branch tracing > for the core runtime. > > Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/ > Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx> > Signed-off-by: Marco Elver <elver@xxxxxxxxxx> > --- > mm/kasan/Makefile | 16 ++++++++-------- > mm/kasan/generic.c | 1 - > 2 files changed, 8 insertions(+), 9 deletions(-) > > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile > index 434d503a6525..de3121848ddf 100644 > --- a/mm/kasan/Makefile > +++ b/mm/kasan/Makefile > @@ -15,14 +15,14 @@ CFLAGS_REMOVE_tags_report.o = $(CC_FLAGS_FTRACE) > > # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 > # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 > -CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_quarantine.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > -CFLAGS_tags_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > +CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_quarantine.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > +CFLAGS_tags_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING > > obj-$(CONFIG_KASAN) := common.o init.o report.o > obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > index 56ff8885fe2e..098a7dbaced6 100644 > --- a/mm/kasan/generic.c > +++ b/mm/kasan/generic.c > @@ -15,7 +15,6 @@ > */ > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > -#define DISABLE_BRANCH_PROFILING > > #include <linux/export.h> > #include <linux/interrupt.h> > -- > 2.26.2.761.g0e0b3e54be-goog > Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Thanks!
